| 摘要 |
The invention provides novel nonsolvated crystals of a polymethine compound which exhibit excellent stability in the form of a solution, high gram absorptivity, excellent storage stability, easy handleability, and high sensitivity to general-purpose semiconductor lasers. Nonsolvated crystals of the polymethine compound represented by formula (I); and a process for the production of nonsolvated crystals of the polymethine compound represented by formula (I), characterized by reacting a polymethine ether compound represented by the general formula (II) with p-toluenesulfonic acid: (I) [wherein TsO is a p-toluenesulfonic acid residue] (II) [wherein R is alkyl, alkoxyalkyl, or optionally substituted aryl].
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